+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Changes in sub-fossil chironomid assemblages in two Northern Patagonian lake systems associated with the occurrence of historical fires

Changes in sub-fossil chironomid assemblages in two Northern Patagonian lake systems associated with the occurrence of historical fires

Journal of Paleolimnology 50(1): 41-56

Patagonia is commonly seen as an exceptionally pristine area because of its wildlife and practically unpolluted waters. However, during the twentieth century the burning of natural forests was one of the most important human activities in Northern Chilean Patagonia. Some estimations indicate that three million hectares were burned during the first three decades of the century. Hence the objective of this study was to evaluate the impacts of the historical fires in Lake Burgos (45 42?S) and Lake Thompson (45 38?S) in Chilean Patagonia. The impact was measured by evaluating chironomid assemblage since they are sensitive enough to be used as an indicator of aquatic ecosystem health. Fires have a direct and drastic effect on a lake watershed but also indirectly affect a lake ecosystem, changing sedimentation patterns or increasing nutrient inputs. In the studied lakes the periods with higher prevalence of fires were identified by charcoal analysis, while organic matter and magnetic susceptibility allowed the confirmation of pre-fire and post-fire periods. The chironomid composition was evaluated through a PCA and an analysis of similarity (ANOSIM) to test the significance among periods while a Detrended Correspondence Analysis was applied to the chironomid assemblage downcore to assess compositional structure and taxa turnover. In Lake Burgos the ANOSIM test indicated significant differences between the pre-fire and fire periods (p < 0.05), while in Lake Thompson differences were not significant. However, in Lake Thompson the PCA clearly separated the pre-fire from the fire period but not the fire from the post-fire periods. In both lakes chironomid composition changed in relation to the period of higher prevalence of fires, which in turn implies catchment changes, pollution, and other anthropogenic impacts. Particularly a marked change in mesotrophic/eutrophic taxa was detected, reflecting an increase in nutrient input due to deforestation. Our findings point out that the lacustrine ecosystems are still affected by the impact of fires and the subsequent increase in nutrient supply that occurred almost 50 years ago. No sign of reverting to pre-disturbance conditions was observed, which makes these lakes highly sensitive to current human-induced impacts.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 036829471

Download citation: RISBibTeXText

DOI: 10.1007/s10933-013-9703-0

Related references

Quantitative palaeotemperature records inferred from fossil pollen and chironomid assemblages from Lake Gilltjarnen, northern central Sweden. JQS Journal of Quaternary Science, 2006

Fossil chironomid assemblages from an oligotrophic lake of Patagonia (Lake Mascardi, Argentina) during the Late-Glacial period. Unknown, 2000

Sub-fossil chironomid assemblages (Diptera: Chironomidae) from the Cerne lake and Prasilske lake (Bohemian Forest, Czech Republic). Silva Gabreta 4: 253-258, 2000

Changes of sub-fossil chironomid assemblages associated with volcanic sediment deposition in an Andean lake (38 degrees S), Chile. Revista Chilena de Historia Natural 80(2): 141-156, 2007

Effects of within-lake variability of fossil assemblages on quantitative chironomid-inferred temperature reconstruction. Palaeogeography, Palaeoclimatology, Palaeoecology 199(1-2): 95-106, 2003

An expanded calibration model for inferring lakewater and air temperatures from fossil chironomid assemblages in northern Fennoscandia. The Holocene 9(3): 279-294, 1999

An expanding calibration model for inferring lakewater and air temperatures from fossil chironomid assemblages in northern Fennoscandia. Holocene 9(3): 279-294, 1999

Are fossil assemblages in a single sediment core from a small lake representative of total deposition of mite, chironomid, and plant macrofossil remains?. Journal of Paleolimnology 48(4): 669-691, 2012

Late glacial summer temperature in the Trentino area (northern Italy) as reconstructed by fossil chironomid assemblages in Lago di Lavarone (1100 m a.s.l.). Studi Trentini di Scienze Naturali: Acta Geologica 82: 299-308, 2007

Late-Holocene summer temperature reconstruction from chironomid assemblages of Lake Anterne, northern French Alps. The Holocene 19.2, 2009

Use of lake fossil diatom assemblages to determine historical changes in trophic status. Canadian Journal of Fisheries & Aquatic Sciences 46(6): 1013-1021, 1989

Chironomid stratigraphy in the shallow and eutrophic Lake Sobygaard, Denmark: chironomid-macrophyte co-occurrence. Freshwater Biology 46(2): 253-267, 2001

The historical range of variability of fires in the Andean-Patagonian Nothofagus forest region. International Journal Of Wildland Fire: 6, 724-741, 2008

Spatial variability of chironomid death assemblages in the surface sediments of a fluctuating tropical lake (Lake Naivasha, Kenya). Journal of Paleolimnology 38(3): 309-328, 2007

Late Holocene environmental changes inferred from diatom, chironomid, and pollen assemblages in an Andean lake in Central Chile, Lake Laja 36degreeS. Hydrobiologia 648(1): 207-225, 2010